Hi ,
Posting a solution I found in another thread,
For the Fluid Grid page(s) you are working on, does the related .css file(s) contain any “Media Queries”? If so, please open the .css file in Dreamweaver CC as a separate file and ensure that the curly braces ‘{‘ for the Media Queries are properly paired (opened and closed) and save the .css file. Then try to open the Fluid Grid page in Dreamweaver CC.
Please let us know if this resolves your issue.
Thanks,
Harish